INTERFACE_LIBRARY: Avoid codepaths which set unneeded properties.

As an INTERFACE_LIBRARY has no direct link dependencies, we can
short-circuit in cmGeneratorExpressionEvaluator and
in cmGlobalGenerator::CheckLocalGenerators.

As they do not generate any output directly, any generate- or install-
related code acn also be short-circuited. Many of the local generators
already do this.

Because only INTERFACE related properties make sense on INTERFACE_LIBRARY
targets, avoid setting other properties, for example via defaults.

1 files changed, 9 insertions, 1 deletions

diff --git a/Source/cmComputeTargetDepends.cxx b/Source/cmComputeTargetDepends.cxx
index 7fd4754..cb9e37e 100644
--- a/Source/cmComputeTargetDepends.cxx
+++ b/Source/cmComputeTargetDepends.cxx
@@ -237,7 +237,15 @@ void cmComputeTargetDepends::CollectTargetDepends(int depender_index)
     it != configs.end(); ++it)
     {
     std::vector<std::string> tlibs;
-    depender->GetDirectLinkLibraries(it->c_str(), tlibs, depender);
+    if (depender->GetType() == cmTarget::INTERFACE_LIBRARY)
+      {
+      // For INTERFACE_LIBRARY depend on the interface instead.
+      depender->GetInterfaceLinkLibraries(it->c_str(), tlibs, depender);
+      }
+    else
+      {
+      depender->GetDirectLinkLibraries(it->c_str(), tlibs, depender);
+      }
     // A target should not depend on itself.
     emitted.insert(depender->GetName());
     for(std::vector<std::string>::const_iterator lib = tlibs.begin();